Earth boring equipment



March 24, 1964 Filed June 1 5, 1960 A. R. PITT ETAL EARTH BORING EQUIPMENT 2 Sheets--Sheei'I 1 wrm ArToRNEYS March 24, 1964 Filed June 15, 1960 A. R. PITT ET AL EARTH BORING EQUIPMENT 2 Sheets-Sheet 2 INVENTORS Aucas R. Plfvf A'rToQNEvS through a full pipe length, at the United States Patent Oiice 3,126,063 Patented Mar. 24, 1964 Filed June 15, 1950 Ser. No. 36,390 Claims priority, appiication Great Britain June 17, 1959 Claims. (Cl. 173-152) Angus R.

This invention relates -to earth drilling rigs of the kind used for drilling deep bore holes, for example in drilling for oil.

A form of drilling rig has been proposed with the object of reducing time lost when changing a drilling bit by providing two power-operated lifts which work alternately over the ysame vertical path to withdraw a string of drill pipe continuously while the individual pipe lengths are automatically unscrewed and stored without stopping the pipe pulling operation. After changing the drilling bit fthe lifts are arranged to run the string of vdrill pipe in continuously, while the individual pipe lengths are automatically added from the store to the string. It has been proposed moreover that during each drilling operatlon the feed of the drill string should -be controlled by one of the lifts, for which purpose a power-operated rotary drive mechanism from which the string is suspended, known as a power swivel is arranged to be carried by the lift.

In a drilling rig as proposed, each lift may operate through a vertical stroke which is not less than the maximum length of a single pipe. Thus when drilling, the string is lowered by the lift which carries the power swivel end of which the string is `supported by ground slips while the lift is raised so that yanother pipe length can be added between the power swivel and the string. The drill-ing operation, though not automatic is carried out in a relatively simple manner using the lift mechanism, power swivel and ground slips.

There are, however, advantages in a drilling rig, according to another proposal, in which the two lifts have vertically displaced ranges of movement with an overlap which enables the upper lift to take over from the lower lift `during pulling, though the two lifts never cross each other. The length of stroke of each lift is in this case litt-le more than half the pipe length.

Advantages which accrue from this arrangement are that the overall height `of the drilling rig can be reduced, and that the problems of designing and using long stroke jacks are greatly eased.

'Ihe present invention is particularly concerned with mechanism for use during 4the drilling operation by a rig constructed in accordance with the latter mentioned proposal.

The present :invention enables the power swivel to move downwardly between the addition of one pipe 'length and the next without interruption, by providing for transfer of the power swivel from the upper lift to the lower lift `during the time when the lifts are moving together through the overlapping region of their strokes.

According to the invention, the upper lift has a location at which the power svw'vel may -be secured by releasable locking means, and from which the power swivel may freely separate downwardly relative thereto when released, while the lower tlift has a location against which the power swivel may be supported or secured when the two lifts are moving together whereby the power swivel is movable with the lower lift upon release of the locking means.

The invention is illustrated by way of example in the accompanying drawings of which:

FIGURE l is a front elevation, mainly diagrammatic,

of the arrangement of lifting jacks and lift platforms in a drilling rig having two lifts which `do not cross each other. For clarity the parts, some of which are in section, are shown in one plane in the diagram;

FIGURE 2 is a plan view from above the upper lift platform; and

FIGURE 3 is a side elevation of the upper and lower -lift platforms shown partly in section on the line [.-II*III of FIGURE 2, together with mechanism carried by the platforms.

FIGURE 1 shows a pair of Vertical guides 9 which are to be understood as being attached to, or forming part of, the drilling rig. An upper pair of vertically extending carriages 22 is provided, as shown in the sectionalized fragment of FIGURE 1, with shafts 2:4 upon which rollers 28 are mounted to run in the guides 9, these guides being of ydouble channel section. An upper lift platform 11i is iixed to the carriages 22, and a lower lift platform 14 is iixed to a pair of lower carriages 23 which are similarly mounted to run in the guides 9. The upper lift platform 10 is carried on the upper ends of the piston rods 11 of a pair of jacks whose cylinders v12 are supported on the base 13 of the rig. The base 13 is not shown in detail but constitutes a support resting on the ground and on which the structure of the rig is mounted. A pair of jacks for the lower lift platform .14 have their piston rods 15 supported on the base 13 while the cylinders 116 are uppermost, the lower lift platform 14 being fixed to the lower end portions of the cylinders 16. The cylinders 16 may rise upwardly through the upper lift platform and the latter is provided with a pair of openings 17 to enable this to be done. The hydraulic jacks for each lift are operated by means which are not shown but which include a connection to liquid pressure for extending the jacks, and throttle valves `for controlling the discharge of liquid from the jacks during contraction.

lFIGURE l shows the upper lift platform iti at the top of its stroke and the lower lift platform 14 near the bottom of its stroke. The lower lift platform 14 is shown in broken lines 14 at the -top of its stroke while the upper lift platform shown in broken lines at liti" near the bottom of its stroke is directly over the top of the lower lift platforms. The two platforms may move together in the overlapping region of their strokes between the levels A and B during which the power swivel `1S can be transferred from one to the other. FIGURE 1y also shows diagrammatically the inclusion of a make and break unit 19 secured to the upper lift platform 11i, and ground slips 21 disposed centrally on the lbase 1.3 `of the rig.

A string of drill pipe V8 is attached to the power swivel 18 and is seen to extend downwardly from the make and break unit 19 and beyond the ground slips 21.

The power swivel 18 comprises a hydraulic motor having pressure and return pipes 25 and 26 and a third pipe Z7 for mud which is to be fed -through a rotatably driven hollow drill pipe adaptor 29 emerging from the base of the hydraulic motor. The drill pipe adaptor 29 is screw threaded in known manner, not shown, to provide a supporting and rotary dri-ving connection with the screw threaded upper end of a drill pipe. The power swivel has three :legs 31 extending downwardly within a circular opening 32 in the upper lift platform 10. tEach leg 31 has a locating hole 33 near its lower end by means of which the leg is secured in the opening 32 by a hydraulic actuated locking pin 34 carried by and projectible radially inwardly Ifrom the upper lift platform 10. A locking pin and its associated hydraulic mechanism is shown in the sectional View in the lower center of FIGURE 2 though in this case it is engaging a lug on the make and break unit which will subsequently be referred to. However, the locking arrangement is the same at all six equally spaced positions around the opening shown in 'FIGURE 2. The locking pin 34 slides through one end of a cylinder 35 and it has an enlarged head 35 engaging the bore of the cylinder 35 while an annular space 3l) surrounds the locking pin 34 between the head 36 and the inner end of the cylinder 35, into which space 3l)` hydraulic liquid may be supplied to retract the pin 34 and from which hydraulic liquid may be released so that the pin can extend under the influence of a spring 37.

The lower lift platform 14 has an opening 38 with an inwardly directed ange 39 at the upper face of the lift platform 14 forming a ledge on which the legs 31 of the power swivel 13 may stand when the two lift platforms and 14 abut each other and the three locking lpins 34 are engaged in the holes 33. The three locking pins 34 are withdrawn by admit-ting hydraulic fluid through duct 50 to the annular spaces 3l), and the power swivel 1S will then be supported solely by the flange 39 on the lower lift .platform 14 without undergoing any movement relative to the two platforms. ln a preferred manner of operating the rig continuously and automatically by control means which is not shown and which forms no part of the present invention, the admission of hydraulic pressure to the quick release locking means may be effected by a valve which is responsive to a fall of pressure in the upper lift jack 11, 12. The power swivel 1S may be centrally located and prevented from turning on the lower lift platform 14 by means of dowel pins 41 which enter registering holes in `the bottom of the legs 31.

The make and break unit 19 is disposed within the opening '32 of the upper lift platform 10, and it has three lugs 43 which are equally spaced between the legs 31 of the power swivel and which have holes 44 therein engageable by the locking pins 34 of the other three hydraulically actuated locking mechanism. The make and break mechanism may similarly rest on the flange 39 and be wholly supported thereby when the locking pins 34 are withdrawn from the lug holes 44.

The make and break unit 19 is conveniently a hydraulically operated mechanism, not shown in detail but of generally known type, having two sets of jaws which respectively grip the drill pipe adaptor shaft 29 and the upper end of the drill pipe and which includes a hydraulic jack to effect relative rotation of the two sets of jaws for making or breaking the screw joint between the shaft 29 and drill pipe '8. The lower lift platform 14 shown -in FlGURB 3 has a slips mechanism shown `generally at 45 lying within the opening 33 `and having three lugs 46 with holes 47 therein for engagement by hydraulically actuated locking pins of the character described in connection with 'FIGURE i2. The slips mechanism 45, which is provided in known manner with gripping wedges, is not essentially used during the drilling operation as the ground slips 21 shown in FIGURE l can support the string of drill pipe when a new pipe is being added, but the slips mechanism 45 can remain in the lower lift platforml 14 with its wedges clear of the drill pipe S and the screw joint thereof, so that it will not interfere with the drilling operation.

The opera-tion of the rig yduring drilling will now be described, starting from the step in the sequence in which the upper lift platform 10 carrying -the power swivel 18 is fully raised. The make and break unit 19 is supported on the flange 39 of the lower lift platform 14 and located by dowels such as the dowels 41 of FIGURE 3. With the make-and-break unit 19, the slips mechanism l45, and the ground slips 21 disengaged from the string of drill pipe, the latter is supported by the drill pipe adaptor 29 and rotated by the hydraulic motor of the power swivel under the supp-ly of fluid pressure in the pipe 25. As the `drilling bit at the lower end of the drill pipe string 8 turns to deepen the bore hole, the upper lift platform 10 is lowered under its own weight and that of the drill pipe string S` at a rate which is controlled by suitably throttling the discharge of liquid from the jacks 1d, 12.

As drilling proceeds, the upper lift platform 10 descends to the region where the ranges of movement of the two lift platforms 1li and 14 overlap and where the lower lift platform 14 is fully raised and waiting. The discharge throttling of the jacks 11, 12 and 15, 16 of the two lifts may be reciprocally changed (by mechanism not hereinV shown) so that the weight supported by the jacks 11, 12 `of the upper lift `decreases as the weight supported by the lower lift jacks 15, 16 increases, whereby the rate of descent of the drill string 8 remains the same. As soon as the weight of the drill string 8 is substantially supported by the lower lift platform 14, the quick release locki-ng means on the upper lift may be operated by means responsive to a fall of pressure in the upper lift jacks 11, 12. The three locking pins 34 holding the power swivel 18 are withdrawn by admitting hydraulic fluid through duct S) to the annular spaces 3i), and the power swivel 18 and the make-andreak mechanism 19 will then be supported solely by the flange 39 on the lower lift platform 14 without undergoing any movement relative to the -two platforms. In a preferred manner of operating the rig continuously and automatically by control means which is not shown and which forms no part of the prescnt invention, the admission of hydraulic pressure to the quick release locking means may be effected by a valve which yis responsive to a fall of pressure in the upper lift jacks 11, 12.

Drilling may be continued without interruption during the transfer of the power swivel 18 vfrom. the upper lift platform to the lower lift platform 14, and during the descent of the latter to the full line position in FIGURE l. Drilling is then suspended by stopping the hydraulic motor of vthe power swivel 1S, and the lower lift 14 is raised sufficiently to take the weight of the drill pipe string off .the drill bit, after which the ground slips 21 are closed on .to the drill pipe 8 to support the weight of same. The make-and-break mechanism 19 is operated to break the joint between the drill pipe S and the drill pipe adaptor 29, and after spinning olf by reverse rotation of the hydraulic motor of the power swivel .18, the latter together with the make-and-break mechanism 19 are raised by the lower lift platform 14 and transferred to the upper lift platform 10 by engagement of the two sets of locking pins 34. The upper lift platform 10 is isilz by the admission of pressure fluid to the jacks When the upper lift platform 1) reaches its upper position a new length of drill pipe can be spun on to the drill pipe adaptor 29' by rotation of the hydraulic motor of the power swivel 18, the joint being then tightened by the make-and-break mechanism 19. The upper lift platform 10 is then lowered sufficiently to enable the new length of drill pipe to be spun on to the top of the drill pipe string S which is supported by 4the ground slips 21. The make-and-break mechanism 19 is then lowered from the upper lift platform 1li to lthe lower lift platform 14, for example by means of an auxiliary winch, not shown, so that it can tighten the newly spun-on 4top joint in the `drill pipe string 3. Finally, the ground slips 21 are released so that the drill pipe string can be rotated and lowered to re-commence drilling. The foregoing cycle is repeated with the addition of each pipe length until the bore hole has reached the required depth, or the drilling bit needs to be changed.

When the drill string is to be withdrawn at the end of a drilling operation, the power swivel 1Sy will be removed from the upper lit-t platform 10* and a slips mechanism, similar to that at 45 on the lower lift platform 14, may be secured to the upper lift platform 10 below the makeand-break mechanism 1?, by the same locking pins 34 which previously secured the power swivel 18. To withdraw the string of drill pipe 8, the slips mechanism 45 is caused to grip the drill pipe below the upper of the screw pipe joints, and the lower lift platform 14 is raised by the hydraulic jacks 1S, le' towards the upper lift platform lil which waits in its lower position. The latter platform l@ can be raised by its hydraulic jacks il, l2 in unison with the lower lift platform ld over the distance in which their respective ranges of movement overlap, at which time the slips mechanism carried by the upper lift platform ll@ is caused to grip the drill pipe 8 at such a position below the screw joint that the two halves of the latter lie in a position to be gripped by the two parts of the make-and-break mechanism 19. The slips mechanism @.5 is then released and the lower lift platform .14 lowered in readiness to grip the pipe length below the next succeeding pipe joint. lMeanwhile the upper lift platform 19 continues to rise and ythe screw joint is broken by the make-and-break mechanism whereupon the uppermost pipe length can be readily spun off. 'The upper lift platform l@ then descends to the position lli where it remains in readiness to take over the lifting of the pipe string from 4the lower lift platform i4.

The subsequent operation of running the drill pipe in again is carried out by a sequence of movements of the various parts which is the reverse of that described in connection with pipe withdrawal.

We claim as our invention:

l. Apparatus for lowering a string of pipe lengths along a vertical axis while rotating the same, comprising vertical guide means which are disposed adjacent the axis, at least t-wo horizontally disposed lift platforms which are mounted one above the other in the guide means for independent movement along the axis and which moreover each define an opening on said axis for purposes of accommodating the pipe lengths, means which are operable to cause the platforms to move along the axis through vertically offset strokes that overlap one another for purposes of moving the platforms over a portion of their respective strokes in adjoining relationship with one another, power swivel means which are operable to support and rotate the string of pipe lengths on the aforesaid axis and which moreover are located initially for the lowering operation in the opening defined by the upper of the two platforms, means which are operable to interlock the power swivel means with the upper platform for purposes of supporting and lowering the power swivel means on and with the latter during that portion of its stroke which does not overlap the stroke of lthe lower of the two platforms, said upper platform opening being sized to pass the power swivel means therethrough and said interlock means being retractable for purposes of disengaging the power swivel means from the upper platform and transferring the same to the lower platform as the two platforms move in adjoining relationship with one another, and means which are disposed on the lower platform about the opening therein for purposes of receiving the power swivel means and locating and supporting the same on the lower platform during at least that portion of its stroke which does not overlap the stroke of the upper platform.

2. Apparatus according to claim .l wherein the interlock means is mounted on one of said upper platform and said power swivel means, and includes a retractable member engaged with the other, to support the power swivel means on the upper platform during the non-overlapping portion of the upper platform stroke.

3. Apparatus accordi-ng to claim 2 wherein the interlock means is mounted on the upper platform and the retractable member includes a radially directed pin, the power swivel means having a radial hole for reception of said pin.

4. Apparatus according to claim 3 wherein the power swivel means includes locating legs extending into and tting closely within the upper platform opening and an aperture in at least one of said legs for receipt of the pin, said pin being mounted in the peripheral wall of the upper platform opening, at a level to engage within said aperture when the legs rest upon the lower platform.

5. Apparatus according to claim 1 wherein last named the means includes upwardly extending pins on the upper face of the lower platform, the power swivel means having apertures to receive said pins and so to prevent lateral displacement between the lower platform and the power swivel means.

6. Apparatus according to claim l further comprising make and break means also disposed initially in said upper platform opening and engageable for movement with said upper platform by the retractable interlock means, said upper platform opening also being of a size to pass the make and break means .therethrough for movement with the power swivel means.

7. An earth drilling rig comprising vertical guide means, at least two horizontally disposed lift platforms, one above the other, guided by said guide means for independent movement along a common vertical axis, the upper one through a range of movement between an upper limit spaced above the upper limit of the platform next beneath the upper one and a lower limit within the upper limit of said lower platform, and the lower one through a range of movement between an upper limit above the lower limit of the upper platform and a lower limit spaced below the latters lower limit, means to move each lift platform through the respective ranges of movement including the common portion, a power swivel including motor means and a rotatably driven output member thereof arranged to support and rotate a string of idrill pipe which extends along the same vertical axis, the lift platforms each having an opening through which the pipe string extends, the opening in the upper lift platform constituting a guide surface engageable with the power swivel -for vertical movement of the latter through the same and for transverse location of the power swivel, releasable locking means interengageable between the upper lift platform and the power swivel, to support the power swivel coaxially within the opening of 4the upper lift platform, and means on the lower lift platform for supportingly engaging the power swivel coaxially when the upper and lower lift platforms are in adjoining positions, moving through the common portion of their ranges of movement, whereby support of the power swivel may be transferred from the upper to the lower lift platform by release of said locking means, or vice versa.

References Cited in the file of this patent UNITED STATES PATENTS 2,126,933 Stone et al Aug. 16, 1938 2,317,306 Smith Apr. 20, 1948 2,716,018 Williams Aug. 23, 1955 

1. APPARATUS FOR LOWERING A STRING OF PIPE LENGTHS ALONG A VERTICAL AXIS WHILE ROTATING THE SAME, COMPRISING VERTICAL GUIDE MEANS WHICH ARE DISPOSED ADJACENT THE AXIS , AT LEAST TWO HORIZONTALLY DISPOSED LIFT PLATFORMS WHICH ARE MOUNTED ONE ABOVE THE OTHER IN THE GUIDE MEANS FOR INDEPENDENT MOVEMENT ALONG THE AXIS AND WHICH MOREOVER EACH DEFINE AN OPENING ON SAID AXIS FOR PURPOSES OF ACCOMMODATING THE PIPE LENGTHS, MEANS WHICH ARE OPERABLE TO CAUSE THE PLATFORMS TO MOVE ALONG THE AXIS THROUGH VERTICALLY OFFSET STROKES THAT OVERLAP ONE ANOTHER FOR PURPOSES OF MOVING THE PLATFORMS OVER A PORTION OF THEIR RESPECTIVE STROKES IN ADJOINING RELATIONSHIP WITH ONE ANOTHER, POWER SWIVEL MEANS WHICH ARE OPERABLE TO SUPPORT AND ROTATE THE STRING OF PIPE LENGTHS ON THE AFORESAID AXIS AND WHICH MOREOVER ARE LOCATED INITIALLY FOR THE LOWERING OPERATION IN THE OPENING DEFINED BY THE UPPER OF THE TWO PLATFORMS, MEANS WHICH ARE OPERABLE TO INTERLOCK THE POWER SWIVEL MEANS WITH THE UPPER PLATFORM FOR PURPOSES OF SUPPORTING AND LOWERING THE POWER SWIVEL MEANS ON AND WITH THE LATTER DURING THAT PORTION OF ITS STROKE WHICH DOES NOT OVERLAP THE STROKE OF THE LOWER OF THE TWO PLATFORMS, SAID UPPER PLATFORM OPENING BEING SIZED TO PASS THE POWER SWIVEL MEANS THERETHROUGH AND SAID INTERLOCK MEANS BEING RETRACTABLE FOR PURPOSES OF DISENGAGING THE POWER SWIVEL MEANS FROM THE UPPER PLATFORM AND TRANSFERRING THE SAME TO THE LOWER PLATFORM AS THE TWO PLATFORMS MOVE IN ADJOINING RELATIONSHIP WITH ONE ANOTHER, AND MEANS WHICH ARE DISPOSED ON THE LOWER PLATFORM ABOUT THE OPENING THEREIN FOR PURPOSES OF RECEIVING THE POWER SWIVEL MEANS AND LOCATING AND SUPPORTING THE SAME ON THE LOWER PLATFORM DURING AT LEAST THAT PORTION OF ITS STROKE WHICH DOES NOT OVERLAP THE STROKE OF THE UPPER PLATFORM. 